Answer this question truthfully
### Question: What causes Abdominal mass?
### Response: Abdominal aortic aneurysm can cause a pulsating mass around the navel. Bladder distention (urinary bladder over-filled with fluid) can cause a firm mass in the center of the lower abdomen above the pelvic bones, in extreme cases it can reach as far up as the navel. Cholecystitis can cause a very tender mass that is felt below the liver in the right-upper quadrant (occasionally). Colon cancer and Volvulus can cause a mass at any location in the abdomen. Crohn's disease or bowel obstruction can cause many tender, sausage-shaped masses anywhere in the abdomen. Diverticulitis can cause a mass that is usually located in the left-lower quadrant. Gallbladder tumor can cause a tender, irregularly shaped mass in the right-upper quadrant. Hydronephrosis (fluid-filled kidney) can cause a smooth, spongy-feeling mass in one or both sides or toward the back (flank area). Kidney cancer can sometimes cause a mass in the abdomen. Liver cancer can cause a firm, lumpy mass in the right upper quadrant. Liver enlargement (hepatomegaly) can cause a firm, irregular mass below the right rib cage, or on the left side in the stomach area. Neuroblastoma, a cancerous tumor, often found in the lower abdomen, that mainly occurs in children and infants. Ovarian cyst can cause a smooth, rounded, rubbery mass above the pelvis in the lower abdomen. Pancreatic abscess can cause a mass in the upper abdomen in the epigastric area. Pancreatic pseudocyst can cause a lumpy mass in the upper abdomen in the epigastric area. Renal cell carcinoma can cause a smooth, firm, but not tender mass near the kidney (usually only affects one kidney). Spleen enlargement (splenomegaly) can sometimes be felt in the left-upper quadrant. Stomach cancer can cause a mass in the left-upper abdomen in the stomach area (epigastric) if the cancer is large. Uterine leiomyoma (fibroids) can cause a round, lumpy mass above the pelvis in the lower abdomen (sometimes can be felt if the fibroids are large). Ureteropelvic junction obstruction can cause a mass in the lower abdomen.